Improving the aesthetics of a low pH (less than about 10, and preferably less than about 9.0) liquid or gel type detergent product (liquid/gel ADW or liqui-gel ADW) is believed to be a very important aspect of this product.
Consumers of liquid ADW products have a preference for liquid ADW products having transparent or translucent characteristics. A transparent or translucent product allows for suspension of colored prills into that product, which can further enhance the physical appearance of the product. The transparent product may be clear, or dyed, using dyes that do not cause significant staining or dyeing of plastics during the wash cycle in automatic dishwashing.
Consumers also have a preference for liquid ADW products that are heavier, i.e., ones that have increased specific gravity. Typically, an increase in specific gravity from about 1.2 grams/ml to about 1.3 grams/ml is deemed to be a significant increase that is appreciated and liked by consumers.
In the low-free water environment of a typical phosphate containing gel type ADW composition, it is a real challenge to obtain clear or translucent characteristics. This is primarily due to the relatively low solubility of commodity phosphate builders, such as sodium tripolyphosphate (STPP), which has a solubility typically of about 14.5 grams per 100 cc of water at room temperature. Previous formulators wishing to obtain clear or translucent characteristics in a liquid or gel type ADW have been forced to use highly soluble potassium tripolyphosphate (KTPP), or alternatively, commercially available mixed sodium and potassium tripolyphosphates (commonly referred to as SKTPP) which have heretofore served a dual purpose of being a potassium source (for transparency/translucency) and a phosphate source (for cleaning performance). The use of KTPP and SKTPP is generally considered undesirable for various reasons, one of them being the economics of manufacturing. Alternatively, the previous formulators have been forced to use very low levels of KTPPs or SKTPs, which detrimentally affects cleaning performance. Thus, a considerable effort has been directed in this field, to develop novel solutions for attaining transparency and/or translucency in liqui-gel ADWs.
For high pH detergent formulations, KOH is the usual potassium source, for not only increasing the specific gravity of the product but also for increasing the alkalinity. However for low pH (less than 10 pH and preferably no more than about 9 pH), the use of KOH in large amounts as a potassium source is undesirable.
There has been an effort directed towards increasing the specific gravity of the liquid product. However, the main drawback is that the present methods employed for increasing specific gravity cause the liquid formulation to lose its transparency, and consequently, this takes away from the product""s aesthetic appeal.
It has been desirable to have liqui-gel ADW products that have a specific gravity closer to a value of 1.3 grams/ml rather than 1.2 grams/ml from an aesthetics standpoint. It has been desirable to have a liqui-gel ADW product having transparency and/or translucency characteristics, but with using no more than 20% by weight, preferably no more than 5% by weight and most preferably 0% by weight (i) potassium tripolyphosphate (KTPP), and/or (ii) commercially available mixed sodium and potassium tripolyphosphate (SKTPP), while at the same time still maintaining high phosphate levels so as to not detrimentally affect cleaning performance.
The inventors of the present invention have discovered that the addition of potassium and ammonium salts in an amount of at least 5% by weight of the detergent composition, serves to increase the specific gravity such that it is aesthetically pleasing which providing a potassium source for transluscency. The inventors of the present invention have also discovered that by maintaining a K:Na weight ratio greater than at least about 0.5:1, K:Na, outstanding translucent characteristics can be imparted without having to use KTPP or SKTPP. Thus, high phosphate levels can be attained by the addition of sodium tripolyphosphate (STPP) alone, along with the addition of potassium salts for low to moderate alkalinity.
The present invention is thus directed to overcome one or more of the problems as set forth before.
The invention meets the needs above by providing a method of increasing specific gravity of a liquid or gel type detergent product which has a pH less than about 10, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, and a transparent or translucent a liquid or gel type detergent product having a pH less than about 10 and a specific gravity of at least about 1.2 grams/ml.
In one aspect of the present invention, the method of increasing specific gravity of a liquid or gel type detergent product having a pH less than about 10.0, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, comprises the steps of: (a) providing a liquid or gel type detergent composition having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) maintaining a potassium:sodium weight ratio greater than at least about 0.5:1; and (c) adding one or more of potassium salts, ammonium salts and mixtures thereof, in an amount of at least 5% by weight of the detergent product.
In another aspect of the present invention, a transparent or translucent a liquid or gel type detergent product having a specific gravity greater than about 1.2 grams/ml and a pH less than about 10.0, comprises: (a) a liquid or gel type detergent composition, the composition having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) a potassium:sodium weight ratio greater than at least about 0.5:1; and (c) one or more of potassium salts, ammonium salts and mixtures thereof, in an amount of at least 5% by weight of said detergent composition.